Disk memory drives generally comprise rotating magnetic memory disks, transducer heads and a linear or pivotally mounted magnetically driven actuator assembly which supports and positions the magnetic transducer heads at the disk surfaces and provides bidirectional movement of the magnetic heads over the disk or disks. Such disk memories are very high precision units requiring close dimensional tolerances in manufacturing. They are complex and delicate mechanically. In application, information stored on the disk must be accessed at high speed. This requires track seeking at high speed and with precision. To minimize power requirements in the servo system which drives the magnetic head suspension assemblies, it is important that the magnetic head suspension assembly be light in weight and yet of sufficient structural rigidity and stability to minimize unwanted magnetic head displacements when track seeking or track following, for example, which would interfere with the rapid positioning and utilization of a magnetic head at a designated track.
Prior art magnetic head suspension assemblies, as seen in the U.S. Pat. Nos. 3,931,641, 4,620,251, 4,754,353 and 4,796,122, typically comprise a rigid arm of aluminum or other lightweight material which is usually a casting of single piece or integrated construction. These castings are provided with projecting fingers or pads on to which the ends of the load beams which carry the magnetic heads are secured. The load beams are flexible and permit spring loaded movement of the magnetic heads in directions toward and away from the head parking disk surface against which the magnetic head is positioned at rest and provide a predetermined preloading of the magnetic head slider rails against a disk surface, so that at disk rotational speed the head takes off and literally flies on the thin film of air clinging to and traveling with the surface of the disk. The heads are usually positioned in a parked position adjacent the center of the disks where there is no recorded information. Thus sliding contact of the sliders on the magnetic heads as the disk comes up to speed in preparation for track seeking, and reading or writing of tracks on the disk, or as the disk decelerates and stops when the disk memory is shut down, will not cause any damage to any of the information which is recorded on the disk surface through damage to the surface of the disk by scraping. These load beams are fabricated of a very lightweight spring metal such as stainless steel which is very thin and has flanged lateral edges to limit flexibility to a location adjacent to the point of load beam attachment to the pad at the end of the suspension arm and to provide stiffness along the length of the load beam. The magnetic head is attached to the free end of the load beam by means of a thin lightweight metal spring material, called a flexure providing flexibility of the magnetic head in roll and pitch, and stiffness in yaw.
As will be seen by reference to these patents, the arm which supports the load beam and which is either mounted for linear or angular movement, is a rigid arm of aluminum as described in U.S. Pat. No. 3,931,641. When viewed with respect to the load beam it is a large, bulky heavy structure constituting the bulk of the magnetic head support and is the primary contributor to a high moment of inertia of the magnetic head suspension assembly.